@jasbrent, you're not wrong, and there's no need for an emergency vet visit.
How much weight has she lost?
Is still losing? If so, how much per day?
Are her poops normal?
Do you notice her drooling, or dropping her food? Those could indicate tooth issues.
A vet visit to have her checked over isn't a bad idea. Older pigs do lose weight, and it's very hard to get a senior pig to gain weight. Don't give her cookies, if you're talking about treats purchased at a pet store. If she doesn't have any calcium problems in her urinary tract, you could give her a glob of Critical Care every day. She'll probably eat it off the plate. That's got good quality nutrition in it, and while it's too high in calcium to be a complete food replacement for a long period of time, it's fine to give a tablespoon or so as a supplement.
But your goal should be stopping any continuing loss, rather than trying to force her to gain weight. Older pigs seem to lose a little, stabilize for a while, lose a little more, stabilize again, lose some more, etc.
Another thing you might try is supplementing with 30-40 mg. of vitamin C for a couple of weeks and see if her appetite picks up, and if she's gaining. Older pigs just don't absorb vitamins and minerals as well as younger ones, and a supplement can often help.
